Development of fueling technologies for modern and future tokamak reactors is essential for their implementation in a commercial energy production setting. Compared to the presently available fueling technologies, gas or cryogenic pellet injection, compact torus injection presents an effective and efficient method for directly fueling the central core of tokamak plasmas. Fueling of the central core of a tokamak plasma is pivotal for providing efficient energy production. The central core plasma of a reactor contains the greatest density of fusion processes. For consistent and continuous fueling of tokamak fusion reactors, compact torus injectors must be operated in a repetitive mode.<p> The goal of this thesis was to study the feasibility of firing the University of Saskatchewan Compact Torus Injector (USCTI) in a repetitive mode. In order to enable USCTI to fire repetitively, modifications were made to its electrical system, control system and data acquisition system. These consisted primarily of the addition of new power supplies, to enable fast charging of the many capacitor banks used to form and accelerate the plasma. The maximum firing rate achieved on USCTI was 0.33 Hz, an increase from the previous maximum firing rate of 0.2 Hz achieved at UC Davis.<p> Firing USCTI in repetitive modes has been successful. It has been shown that the CTs produced in any given repetitive series are properly formed and repeatable. This is made evident through analysis of data collected from the CTs' magnetic fields and densities as they traveled along the injector barrel. The shots from each experiment were compared to the series' mean data and were shown to be consistent over time. Calculations of their correlations show that there are only minimal deviations from shot to shot in any given series.

Development of fueling technologies for modern and future tokamak reactors is essential for their implementation in a commercial energy production setting. Compared to the presently available fueling technologies, gas or cryogenic pellet injection, compact torus injection presents an effective and efficient method for directly fueling the central core of tokamak plasmas. Fueling of the central core of a tokamak plasma is pivotal for providing efficient energy production. The central core plasma of a reactor contains the greatest density of fusion processes. For consistent and continuous fueling of tokamak fusion reactors, compact torus injectors must be operated in a repetitive mode.<p> The goal of this thesis was to study the feasibility of firing the University of Saskatchewan Compact Torus Injector (USCTI) in a repetitive mode. In order to enable USCTI to fire repetitively, modifications were made to its electrical system, control system and data acquisition system. These consisted primarily of the addition of new power supplies, to enable fast charging of the many capacitor banks used to form and accelerate the plasma. The maximum firing rate achieved on USCTI was 0.33 Hz, an increase from the previous maximum firing rate of 0.2 Hz achieved at UC Davis.<p> Firing USCTI in repetitive modes has been successful. It has been shown that the CTs produced in any given repetitive series are properly formed and repeatable. This is made evident through analysis of data collected from the CTs' magnetic fields and densities as they traveled along the injector barrel. The shots from each experiment were compared to the series' mean data and were shown to be consistent over time. Calculations of their correlations show that there are only minimal deviations from shot to shot in any given series.

A three-beam heterodyne polarimeter has been designed and constructed to measure line-integrated density and Faraday rotation of accelerated spheromak plasmas in the Plasma Injector 1 and 2 devices (PI-1, PI-2) at General Fusion Inc. Faraday rotation is a function of the local magnetic field and electron density. Therefore, the polarimeter has the potential to provide information on the internal magnetic field of the plasma. A typical spheromak is about 1m in length and is accelerated to speeds on the order of 100km/s. At a bandwidth of 1MHz, the polarimeter can axially resolve the spheromak down to about 10cm. The polarimeter uses a $\nit{CO}_2$ laser that produces a Faraday rotation signal of about $0.5\degrees$ for a typical plasma with density and magnetic field on the order of $\ee{21}\mmt$ and 1T. The Faraday rotation measurement noise floor for a null signal is about $0.1\degrees$. Two important sources of Faraday rotation error are the ellipticity and collinearity of the plasma-immersed beams. These error sources are examined by sending the plasma beams through a rotating optic to mimic the path through a dense, magnetized plasma. The error due to the ellipticity effect has been reduced to below the noise floor by careful alignment and use of zero phase reflectors that minimize elliptical polarization of the beams. Collinearity error has been greatly improved by aligning the beams with a rotating ZnSe wedge. Measurements after the alignment match well with a model Faraday rotation signal generated from magnetic probe measurements. However, beam collinearity continues to be a significant source of error. For regions with strong density gradients, the size of this error can be on the order of the signal magnitude. For future work, steps should be taken to improve the alignment of the two plasma-immersed beams, and to shorten the length of the beam path to further reduce the beam collinearity error. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2014-04-30 22:17:18.648